Chemistry (NTSE/Olympiad)  

4. Structure Of Atoms


Electron was discovered by J.J. Thomson. Cathode rays consist of small, negatively charged particles called electrons. The electron is a negatively charged particle found in the atoms of all the elements. The electrons are located outside the nucleus in an atom. An electron is usually represented by the symbol e
Characteristics of an electron
Mass of an electron :
The mass of an electron is about of the mass of hydrogen atom. Since the mass of a hydrogen atom is 1 u. The absolute mass of an electron is, however, 9 × 10–28 gram.
Charge of an electron :
The absolute charge on an electron is 1.6 × 10–19 coulomb of negative charge. The relative charge of an electron is, – 1.


NTSE Chemistry (Class X)

NTSE Chemistry (Class IX)


NTSE Physics Course (Class 9 & 10)

NTSE Chemistry Course (Class 9 & 10)

NTSE Geography Course (Class 9 & 10)

NTSE Biology Course (Class 9 & 10)

NTSE Democratic Politics Course (Class 9 & 10)

NTSE Economics Course (Class 9 & 10)

NTSE History Course (Class 9 & 10)

NTSE Mathematics Course (Class 9 & 10)